1. Field of the Invention
The present invention generally relates to components of steerable independent front suspension assemblies and, more particularly, is concerned with a steering knuckle carrier-to-suspension arm pivotal connection and a method of assembling and preloading the pivotal connection.
2. Description of the Prior Art
A conventional steerable independent front suspension (IFS) assembly for a wheeled vehicle, such as a car or truck, typically includes a steering knuckle, a carrier having a kingpin aperture, upper and lower suspension arms pivotally supporting the carrier and provided in a generally wishbone configuration therewith, and a kingpin received in the kingpin aperture and pivotally supporting the steering knuckle on the carrier. The kingpin is usually disposed in an inclined relationship to a vertical reference so as to exhibit camber such that good steering stability is provided. The steering knuckle has a spindle which extends outwardly and upon which a wheel and brake assembly is adapted to be mounted. The steering knuckle is articulated relative to the carrier by a steering linkage assembly. An example of this IFS assembly is disclosed in U.S. Pat. No. 6,116,626 to Cherry et al. Another example is known as a Dana/Kirkstall IFS84 assembly.
Each of these conventional IFS assemblies has utilized pivotal connections respectively between the upper and lower ends of the steering knuckle carrier and the corresponding upper and lower wishbone suspension arms. Each pivotal connection typically includes a pair of opposing bearing assemblies disposed within a bore defined through the respective one of the upper and lower ends of the steering knuckle carrier and an attachment member disposed through the bearing assemblies with opposite ends of the attachment member secured to the outer ends of the corresponding one of the upper and lower wishbone suspension arms such that the steering knuckle carrier can pivot relative to the wishbone suspension arms. In the case of the Cherry et al. assembly, the attachment member is a pin (or bolt) having a nut threadably secured on one end thereof. In the case of the Dana/Kirkstall IFS84 assembly, the attachment member is a pivot arm spindle (or bolt) having a stake nut threadably secured on one end thereof. In both cases, by threadably tightening the respective nuts relative to the bolts or attachment members to a specified torque, the desired preload is applied to the bearings of the pivotal connection. Also, in the case of the Dana/Kirkstall IFS 84 assembly, an annular groove is formed in each end of the steering knuckle carrier surrounding the bore at a central location and a circlip is placed in the annular groove such that the circlip is disposed between the opposing bearings. When the nut is threadably tightened relative to the bolt or attachment member the bearings become pressed against and clamped to the opposite sides of the circlip in the process of applying the desired preload force to the bearing assemblies of the pivotal connection.
Problems exist with pivotal connections which employ bolts and threadably nuts to retain the bearing assemblies under a desired level of preload force clamped to the opposite sides of circlip in the bore of the carrier. The use of the machined central groove and installation of the circlip in the carrier groove increases installation complexity and the cost of the pivotal connection. Preload clamping the bearing assemblies between mounts on the ends of the suspension arms and the central circlip by tightening a bolt and nut to a specific torque and then staking the nut to prevent loosening is inherently imprecise due to the employment of a widely variable torque tension type of preloading and thus is inconsistent from one pivotal connection to the next.
Consequently, a need still exists for an innovation in the makeup and assembling of these pivotal connections which will provide a solution to the aforementioned problem in the prior art without introducing any new problems in place thereof.
The present invention provides a steering knuckle carrier-to-suspension arm pivotal connection and a method of assembling and preloading the pivotal connection which are designed to satisfy the aforementioned need. The pivotal connection and its method of assembling and preloading of the present invention employs features which reduces installation complexity and the cost of the pivotal connection, permits the use of interchangeable components from one pivotal connection to the next, and greatly enhances the precision and consistency of the pivotal connections by employment of a forced placement type of preloading of the bearing assemblies.
Accordingly, the present invention is directed to a steering knuckle carrier-to-suspension arm pivotal connection. The pivotal connection comprises: (a) an annular member centrally located along and projecting radially into a bore through a steering knuckle carrier; (b) a pin extending through the bore and having an annular flange formed around and projecting radially outwardly from and proximate one end of the pin and an annular groove formed around and projecting radially inwardly into and proximate an opposite end of the pin; (c) a pair of opposing annular bearing assemblies disposed around the pin and located between the one and opposite ends thereof and having components rotatable relative to one another fitted around the pin and within the bore of the carrier on opposite sides of the annular member in the bore such that the pin is rotatable relative to the carrier, both of the annular bearing assemblies abutting opposite sides of the annular member in the bore, one of the annular bearing assemblies abutting a side of the annular flange on the pin and the other of the annular bearing assemblies being spaced from the annular groove in the pin so as to define an annular gap extending from the annular groove to the other annular bearing assembly; (d) a retainer member disposed in the annular groove in the pin and projecting radially outwardly beyond the pin and spaced by the annular gap from the other annular bearing assembly; (e) means positioned around the pin between the retainer member and the other annular bearing assembly so as to fill the annular gap in a manner that imposes a predetermined preload force on the annular bearing assemblies that causes the annular bearing assemblies to clamp therebetween the annular member in the bore of the carrier; and (f) means disposed at opposite ends of the pin for attaching the pin to a suspension arm.
The present invention also is directed to a method of assembling and preloading the pivotal connection comprising the steps of: (a) providing an annular member centrally located along and projecting radially into a bore through a steering knuckle carrier; (b) providing an elongated pin having an annular flange formed around and projecting radially outwardly from and proximate to one end of the pin and an annular groove formed around and projecting radially inwardly into and proximate to an opposite end of the pin; (c) placing the pin and a pair of annular bearing assemblies within the bore such that the bearing assemblies are dispose around the pin between the flange and groove thereof in abutting relationship with opposite sides of the annular member in the bore with one of the bearing assemblies also abutting the flange of the pin and the other of the bearing assemblies being spaced from the groove of the pin so as to define a gap therebetween and with the bearing assemblies having respective components rotatable relative to one another and respectively being fitted around and in contact with the pin and within and in contact with the bore of the carrier such that the pin is enabled to rotate relative to the carrier; (d) installing a spacer ring about the pin adjacent to the other bearing assembly and the groove in the pin; (e) applying a predetermined preload force against the spacer ring in the direction of the bearing assemblies so as slide the spacer ring toward the other bearing assembly and away from the groove; (f) installing a retainer ring in the annular groove; (g) measuring the width along the pin of a space left between the spacer ring and retainer ring and predetermining the number of annular shims it takes to fill the space; (h) removing the predetermined preload force and the retainer ring; (i) installing the predetermined number of annular shims along with the spacer ring around the pin in the gap between the annular groove in the pin and the other bearing assembly; (j) reapplying the predetermined preload force against the spacer ring and annular shims in the direction of the bearing assemblies so as slide the spacer ring and annular shims toward the other bearing assembly and away from the groove; and (k) reinstalling the retainer ring in the groove so as to retain the spacer ring and annular shims around the pin so as to fill the gap in a manner that imposes the predetermined preload force on the bearing assemblies that causes the bearing assemblies to clamp therebetween the annular member in the bore of the carrier.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.